Servicing and assembly: enabling the most ambitious future space observatories

The scientific measurement requirements of future major space astronomy missions are pushing the design limits that can be autonomously deployed JWST-style from even the largest plausible launch vehicles in the 2030s and beyond. In addition, to maximize the scientific return and make missions more cost-effective, they should be capable of being serviced and upgraded. This requirement was even codified by the US Congress in 2010 to ensure the best use of taxpayer investments in science. We need to advance technologies to support this new generation of space telescopes and utilize planned NASA assets to lower costs, reduce risks, and extend mission life of flagship-class science programs for astrophysics and other NASA science. These missions will be capable of searching very large numbers of extrasolar planets for evidence of life and will enable studies, in detail, of the structure of the first star-forming complexes in the earliest galaxies and the central engines in distant galaxies, and will be powerful tools for general astrophysics and solar system science. We will present and discuss current concepts for using astronauts and robots to service, upgrade, and eventually assemble space observatories and starshades designed to achieve major breakthroughs in our understanding of the cosmos. Notional telescopic missions and instruments (filled apertures, interferometers, evolvable systems, and starshades, among others) will be used to illustrate key characteristics of this approach and demonstrate the broad application such a deep-space facility would provide science missions. The goal of this effort is to understand how to use planned NASA human spaceflight assets and infrastructure, with minimal modification, to assemble, test, and service high-value science facilities. These deep space assets are currently being defined and now is the time to jointly develop requirements and capabilities that meet both science and human exploration objectives. The technical and engineering merits and challenges of in-space servicing and assembly will be discussed, including issues of launching telescopes and instruments in parts, assembly in space, and repair and replacement of instruments and systems. Possible future space infrastructure that may make on-orbit assembly and servicing feasible will also be discussed. Precursors and demonstration activities will be presented, as well as early candidate missions for in-space upgrade and servicing.